Magnetic cell sorting and flow cytometry sorting methods for the isolation and function analysis of mouse CD4＋ CD25＋ Treg cells

Objective: In this paper we compared the two methods of cell sorting (magnetic cell sorting and flow cytometry sorting) for the isolation and function analysis of mouse CD4~+ CD25~+ regulatory T (Treg) cells, in order to inform further studies in Treg cell function. Methods: We separately used magnetic cell sorting and flow cytometry sorting to identify CD4~+ CD25~+ Treg cells. After magnetic cell separation, we further used flow cytometry to analyze the purity of CD4~+ CD25~+ Treg cells, trypan blue staining to detect cell viability, and propidium iodide (PI) staining to assess the cell viability. We detected the immune inhibition of CD4~+ CD25~+ Treg cells in the in vitro proliferation experiments. Results: The results showed that compared to flow cytometry sorting, magnetic cell sorting took more time and effort, but fewer live cells were obtained than with flow cytometry sorting. The CD4~+ CD25~+ Treg cells, however, obtained with both methods have similar immunosuppressive capacities. Conclusion: The result suggests that both methods can be used in isolating CD4~+ CD25~+ Treg cells, and one can select the best method according to specific needs and availability of the methodologies.     

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Thigh muscle volume is a useful determinant of functional fitness. However, anthropometric prediction of muscle content is influenced by the variability of adipose tissue accumulation. The aims of this study were to predict thigh muscle and adipose tissue volumes from anthropometry and to assess the validity of the method by examining the various components of the measurements and the assumptions involved. The 19 participants (9 men, 10 women; age 23-49 years) varied in adiposity. They all underwent magnetic resonance imaging (MRI) of the upper leg and the eight men and two women with the lowest adiposity underwent detailed anthropometry involving girths and skinfolds. Using MRI as the reference method, muscle volume was predicted from anthropometry using a circular concentric model, and the assumptions inherent in the method were tested further using the MRI data alone. Muscle volume was best predicted by anthropometry in the 10 leanest participants using a five-slice truncated cone model that overestimated the mean MRI value by 30% ( R 2 = 0.95; standard error of estimate = 288 cm 3 ; P ? 0.001). A single skinfold plus girth measurement at the mid-thigh almost matched its predictive ability, but with an increased bias. Measurements of leg circumference by means of the two techniques agreed well. The assumption of a circular cross-section was valid. In contrast, the agreement between skinfold thickness measured by caliper and superficial adipose tissue thickness by MRI was poor, contributing to the scatter of fat and lean area comparisons. An anterior skinfold thickness measurement underestimated the area of superficial adipose tissue at that level, particularly at the most proximal and distal sites. Although these limitations increase the uncertainties of muscle volume determination by anthropometry, they do not prevent its valid prediction in leaner individuals. The prediction of superficial adipose tissue was poorer.     

Effect of creatine supplementation on phosphocreatine resynthesis,inorganic phosphate accumulation and pH during intermittent maximal exercise

In this study, we examined the effect of creatine ingestion on muscle power output, muscle phosphocreatine resynthesis, inorganic phosphate and pH during repeated brief bouts of maximal exercise. Nine healthy males performed maximal plantar flexion before and after creatine ingestion (20 g ·day -1 for 6 days). The experimental protocol consisted of five 8 s bouts (bouts 1-5) interspersed with 30 s recovery, followed by bouts 6 (8 s) and 7 (16 s) separated by 1 and 2 min, respectively. Muscle phosphocreatine, inorganic phosphate and pH were estimated every 16 s by 31 P magnetic resonance spectroscopy. After creatine ingestion, muscle power output increased by ~5% ( P ? 0.05) from bouts 3 to 7 and muscle phosphocreatine resynthesis increased ( P ? 0.05) during 10 min recovery. The higher phosphocreatine concentration observed after only 30 s of recovery was accompanied by lower inorganic phosphate accumulation and higher pH. Strong correlations were found between exercise power restoration and the corresponding pre-exercise phosphocreatine and inorganic phosphate concentrations and muscle pH after creatine ingestion. The better maintenance of muscle power output observed after creatine ingestion was attributed to a higher rate of phosphocreatine resynthesis, lower accumulation of inorganic phosphate and higher pH.     

Creatine kinase,myosin heavy chains and magnetic resonance imaging after eccentric exercise

The aim of this study was to examine the relationship between myosin heavy chain (MHC) release as a specific marker of slow-twitch muscle fibre breakdown and magnetic resonance imaging (MRI) of skeletal muscle injury after eccentric exercise. The effects of a single series of 70 high-intensity eccentric contractions of the quadriceps femoris muscle group (single leg) on plasma concentrations of creatine kinase and MHC fragments were assessed in 10 young male sport education trainees before and 1 and 4 days after exercise. To visualize muscle injury, MRI of the loaded thigh was performed before and 4 days after the eccentric exercise. All participants recorded an increase ( P ? 0.05) in creatine kinase after exercise. In five participants, T2 signal intensity was unchanged post-exercise compared with pre-exercise and MHC plasma concentration was normal; however, they showed an increase ( P ? 0.05) in creatine kinase after exercise. For the remaining five participants, there was an increase in T2 signal intensity of the loaded vastus intermedius and vastus lateralis. These changes in MRI were accompanied by an increase in MHC plasma concentration ( P ? 0.01) as well as an increase in creatine kinase ( P ? 0.01). We suggest that changes in MRI T2 signal intensity after muscle damage induced by eccentric exercise are closely related to damage to structurally bound contractile filaments of some muscle fibres. Additionally, MHC plasma release indicates that this damage affects not only fast-twitch fibres but also some slow-twitch fibres.     

利用生物质甘蔗制Z造生物基聚乙烯醇高分子材料的优势探讨

概述了高分子材料聚乙烯醇的发展现状,对以甘蔗为原料开发"生物质乙烯制生物基高分子材料-聚乙烯醇"产品的发展,市场、技术、经济等方面的优势进行了深入分析,阐明了不断发展生物质乙烯法制生物基高分子材料聚乙烯醇等生物质化工产业群是广西生物质甘蔗深化利用的有效途径。     

Dynamic Monte Carlo study on the probability distribution functions of tail-like polymer chain

INTRODUCTION Polymer chains with one end attached to a sur- face by means of physical or chemical interaction have become one of the important polymer science subject, which are useful for many applications, such as polymer compatibilizers, copolymer microphases, colloid stabilization, polymeric surfactants (Milner, 1991). Grafting polymers can improve the power efficiency of electrorheological fluids, enhance pho- toluminescence of nano materials, and increase dis- persion stability. On …     

粘度及流变性在实验教学中的应用

物理化学实验主要针对物质的性质进行表征,传统的粘度测定方法是用乌氏粘度计测定高聚物的粘度。为了增强专业特色,为了加强学生的综合素质、创新意识的培养,为了使实验更接近现代实验教学的要求,设计选用了先进的旋转粘度计测量物质的粘度及其流变性。     

溶胶-凝胶技术在化学领域中的新应用

溶胶－凝胶（sol-gel)技术是一种很有发展前途的固体材料制备方法，已众多领域重视。本简要综述了sol-gel技术在合成无机纳米材料，合成无机／有机杂化聚合物，以及在化学生物传感器研究领域中的新应用。     

Strengthening reinforced concrete beams using prestressed glass fiber-reinforced polymer-Part Ⅰ: Experimental study

This work is aimed at studying the strengthening of reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP). Carbon fiber-reinforced polymer (CFRP) has recently become popular for use as repair or rehabilitation material for deteriorated R. C. structures, but because CFRP material is very stiff, the difference in CFRP sheet and concrete material properties is not favorable for transferring the prestress from CFRP sheets to R. C. members. Glass fiber-reinforced polymer (GFRP) sheets with Modulus of Elasticity quite close to that of concrete was chosen in this study. The load-carrying capacities (ultimate loads) and the deflections of strengthened R. C. beams using GFRP and PGFRP sheets were tested and compared. T- and ⊥-shaped beams were used as the under-strengthened and over-strengthened beams. The GFRP sheets were prestressed to one-half their tensile capacities before being bonded to the T- and l-shaped R. C. beams. The prestressed tension in the PGFRP sheets caused cambers in the R. C. beams without cracks on the tensile faces. The PGFRP sheets also enhanced the load-carrying capacity. The test results indicated that T-shaped beams with GFRP sheets increased in load-carrying capacity by 55% while the same beams with PGFRP sheets could increase load-carrying capacity by 100%. The ⊥-shaped beams with GFRP sheets could increase load-carrying capacity by 97% while the same beams with PGFRP sheets could increase the loading-carrying capacity by 117%. Under the same external loads, beams with GFRP sheets underwent larger deflections than beams with PGFRP sheets. While GFRP sheets strengthen R. C. beams, PGFRP sheets decrease the beams' ductility, especially for the over-strengthened beams (⊥-shaped beams).     

Planum temporale asymmetry: In-vivo morphometry affords a new perspective for neuro-behavioral research

High-resolution magnetic resonance (MR) imaging today allows the in vivo quantification of the surface area of the cortex covering the planum temporale and permits assessment of the direction and degree of individual left-right asymmetry of this structure. This methodologic advance is promoting new studies on the biological mechanisms of anatomic and functional lateralization and on the structural accompaniments of disorders such as developmental dyslexia. It is important to stress that studies must agree on the definition and measurement of planum asymmetry, and we review our definition and its justification in the present article.Data obtained from normal subjects supported the assumption that planum (a)symmetry underlies functional lateralization. Thus, familial sinistrality predicted for symmetry of the planum in all eight left-handers studied. The pattern of planum symmetry in the normals was similar to that found in the post mortem studies of dyslexic individuals. Insofar as hand preference and developmental dyslexia are in part genetically transmitted, we suggest that planum symmetry may represent an inherited condition as well. Further-more, even though planum symmetry is part of the anatomic substrate of developmental dyslexia, it is unlikely that it represents a form of developmental anatomic pathology.